search for: jmoreira

Dear members of R-list, I need to reproduce the rules of a decision tree. For that I need to use the csplit information from the rpart.object. But I cannot uderstand the information because from my example I get: > rpart.tree$csplit [,1] [,2] [,3] [,4] [,5] [,6] [,7] [1,] 1 3 3 1 3 3 3 [2,] 2 3 3 1 2 2 2 [3,] 1 3 3 1 3 3 3

Hello to everybody, Does anyone has implemented a function for evaluating models using windowing strategies, such as growing window or sliding window ones? The aim is to evaluate regression models on a time series data. I do not use cross-validation once data sorted in a radom way does not make sense when evaluating time series. Thanks Joao Moreira

Heloo, I have the following problem: orig.data <- NULL Inside a loop I have instructions like: orig.data <- rbind(orig.data, ...) After that I do: colnames(orig.data)<-c('Data','InicioViagem', ...) Everything works fine. For example, the first line of the matrix is: > orig.data[1,] Data InicioViagem ... 1 40466 ... The problem is: I

Hello, I am feeling that this question can have a very simple answer, but I can't find it. I need to use the function knn.dist from knnflex library. Whatever I try, I get the error: Error in as.vector.dist(x, "character") : unused argument(s) ("character") First example: > a<-NULL > a<-rbind(a,c(5.2,-8.1)) > a<-rbind(a,c(8.8,-16.1)) >

Hello, I am doing intensive tests on SVMs parameter selection. Once a while I got the error: Error in save.image(): image could not be renamed and is left in .RDataTmp1 I cannot use the information saves in .RDataTmp1. When that happens I loose several hours of tests. It happens, ussualy when the computer is locked, i.e., there is not other relevant processes running on. I can do tests and get

Hello, As far I saw in archive mailing list, I am not the first person with this problem. Anyway I was not able to pass this error once the information I got from the archive it is not very conclusive for this case. I have used linear, radial and sigmoid kernels for the same data in the same conditions and everything is ok. This problem just happens with the polynomial kernel. I send the

Dear list, I am trying to do a benchmark study for my case study. It is a regression problem. Among other models I use randomForest. Using the following code the result is around 0.628, and this make sense comparing with other methods. The Theil function implements Theil's U statistic. I do not present the definition of some variables because it is not important to understand my problem.

Hello, I am using SVM under e1071 package for nu-regression with 18 parameters. The variables are ordered factors, factors, date or numeric datatypes. I use the linear kernel. It gives the following error that I cannot solve. I tryed debug, browser and all that stuff, but no way. The error is: Error in get(ctr, mode = "function", envir = parent.frame())(levels(x), :

Hello, I am using projection pursuit regression parameters selection. Does anyone has experience on the range to test for df parameter (spline kernel) and gcvpen (gcvspline kernel)? I don't find any information about this. Thanks in advance. Joao Moreira [[alternative HTML version deleted]]

Dear mailinglist members, I have the following problem: I run a decision tree using the rpart function and, afterwords, I try to find to which leaf node a new register (not used to build the decision tree) belongs to. I will try to explain better: rpart.tree <- rpart(target.value ~., data) leaf.node <- new.function(rpart.tree, new.register) The new register has all the explanatory values

Dear all, I have been doing tests using SVM, random forests and PPR. The data is from a data stream (that is, the data for training and for test is always increasing / changing). With SVM and random forests everything is ok, but with ppr there are situations where it crashes. For the examples I have used I noticed that if one of the variables has just one value (it can happen), it crashes for

Hello, I want to create a data.frame with different number of columns per line. What I want is something like: example <- NULL begin <- 1 while (end < nrow(orig.data)) { end <- next.day(orig.data,begin) # my own function. It returns the first index from the next day. Each day has a different number of records. example <- rbind(example, c(begin, end, predictions[c(begin:end)],

Hello, I have the following problem: test is a data frame with 9 fields. The field test$Date is factorized with dates. The format is dd-mm-yyyy (using Oracle notation). I want to convert this to Date in '%Y-%m-%d format. What I am doing is: for (i in 1:nrow(test)) { test[i,]$Data<-strptime(substring(test[i,]$Data,1,10),"%d-%m-%Y") } test is a data frame. The error is: